The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)
site maintained by the Florida
Cooperative Extension Service.

The faculty and staff of the ARC-Apopka are pleased you have taken
the opportunity to meet with us and view our current research.
We have divided the Center's research activities into 5 program areas,
as specified in this pamphlet. Faculty members (with a name tag and green
ribbon) can be found at six locations and will lead a brief discussion and
answer any questions you may have concerning their program. Check the
attached list and location map for experiments you are particularly inter-
ested in observing. Some locations have experiments which are not included
in a discussion. Feel free to visit any and all locations and be sure to
locate (and sample!!) our refreshments during your journey.
Have a good day.

ARC-A Faculty and Staff

ENTOMOLOGY PROGRAMS
Discussion Leader L. S. Osborne, Entomologist
Location 4
A. Controlling Maranta mite.
One of the most critical problems affecting Maranta production during
the last few years has been a mite. This mite, Steneotarsonemus furcatus,
or "Maranta mite", can devastate plantings of both green and red maranta.
Work conducted by Denmark and Nickerson with the Division of Plant Industry
indicated that many of the common miticides are ineffective in controlling
this problem. During the past year (1983), we have found a method for con-
trolling Maranta mite and thus, enable growers to produce quality plants.

Fifty heavily infested plants were obtained from a local grower. Twenty-
five were sprayed 3 times at weekly intervals with the labeled rate of
Thiodan 2E (1 qt/100 gal) and the remaining plants were sprayed with
water. After the final treatment, each plant was rated as being infested
(+) or mite free (-). There were no mites found on any of the Thiodan
treated plants compared to a 76% infestation of untreated plants. No
phytotoxicity has been reported on Maranta as a result of using Thiodan
2 EC. (Ref. Entomology Circular #229 and FSHS 94[81]:70-72). Symptoms
caused by the Maranta mite are on display.
B. Evaluation of Safer Agro-Chem's Insecticidal Soap for the control of mites.
Work has been completed which shows that this soap is as effective
as P2nta when sprayed in the interior environment for mite control on
ornamentals (Table 1 see Research Report 82-2). Tests will be underway
evaluating phytotoxicity and efficacy (Table 2) of this material when
used to control two-spotted spider mites on Schefflera. We will also be
evaluating the potential for using soap in conjunction with predatory
mites as part of our IPM programs.

Table 1. Comparison of Safer's Soap and Pentac 50 WP for the control
of spider mites on B. actinophylla under interior conditions.

C. Don't drench when you are told to spray_
Insecticides registered for use as foliar sprays can cause severe
problems if they reach the root system of the plant. A demonstration
will be available for viewing which will show phytotoxicity associated
with soil drenches and foliar sprays with excess runoff (See research
report 83-7).
Treatments in this demonstration will include the following:
1) Soil drench
2) Spray to runoff
3) Spray to runoff but pesticide is prevented from reaching the soil
4) H20 spray and drench

D. Insect diseases.
All living animals and plants are susceptible to disease-causing
organisms. A new direction in controlling insects and mites is the use
of host-specific pathogens. These pathogens have been used in other
pest management systems quite effectively. We will have a short dis-
cussion on this topic as well as a demonstration showing diseased or
dead insects.

E. Influence of insecticides on leaf spot diseases.
Work has been completed which demonstrates that some commonly used
insecticides affect the incidence and severity of fungal leaf spots on
a number of host plants. Acephate soap and oxamyl both reduce the
severity of Alternaria leaf spot of Brassaia actinophylla (Table 1).
The results of this study will be demonstrated. See research reports
82-25 and 83-8 and Table 2 for more information.

FERN PROGRAMS
Discussion Leader D. D. Mathur, Fern Specialist
Location 11
A. Vase life of antitranspirant-treated leatherleaf fern.
Research was initiated to determine effects of length of storage
on vase life of antitranspirant-treated cut leatherleaf fern. Vase
life of untreated fern in June and August was between 6 and 7 days.
Dip application of the antitranspirants, a paraffin wax emulsion
(Mobilcer A) and a polyvinyl chloride complex (Wiltpruf), at 2, 1
and .5% produced a 2 to 3-fold increase in the vase life of cut
leatherleaf fern. Research has also shown that Vapor Gard which is
readily available at 0.5% was equivalent to the above materials.

B. Effect of minor elements on yield and vase life of leatherleaf fern.
The effect of certain minor elements on fern wilt is being tested
on fern grown under 73% polypropylene shade and fertilized at 1000 lb
N/A/yr from 19-6-12 (N-P205-K20) granular fertilizer. Treatments
include aluminum at 10 and 20 Ib/A/yr; boron, 1 and 2 lb/A/yr; copper,
5 and 10 lb/A/yr and magnesium at 50 and 100 Ib/A/yr. Results obtained
show that aluminum, boron, copper and magnesium do not affect either
yield or vase life of leatherleaf fern.

Location 12
A. Effect of nitrogen source and rate on leatherleaf fern.
In recent years, growers have reported premature wilt of leatherleaf
fern beginning in May, peaking in August-September, and diminishing in
December. This research was established to determine the effect of
nitrogen source and rate of application on yield and vase life of
leatherleaf fern.
Leatherleaf fern grown under 73% polypropylene shade was fertilized
monthly (N-P-K-Mg) at 2 rates: 1) 500-250-500-100 lb/A/yr and 2) 1000-
500-1000-200 Ib/A/yr, with 100% urea, 100% ammonium, 50% urea + 50%
nitrate, 50% ammonium + 50% nitrate and no fertilizer for a 3-year period.
Frond yield was highest at 50% ammonium + 50% nitrate at 500 Ib/A/yr.
Fertilization with urea at 500 and 1000 Ib/A/yr did not increase yield
compared to the control fern. Frond vase life was not affected by
these treatments.
B. Weed control in tree fern (Asparagus virgatus).

Karmex and Princep have been used to control weeds in Asparagus
setaceus (Asparagus plumosus). These compounds, plus Banvel D are
being tested in this experiment for phytotoxicity to A. virgatus. If
the level of toxicity of the chemicals is negligible or acceptable,
combinations will be tested for weed control. Banvel D is primarily
a postemergent herbicide (kills existing weeds), while Karmex and
Princep at rates used are preemergent herbicides (prevent weed infes-
tation). Results can be viewed.
Treatments Al/acre
1. Hand weeded monthly
2. 0.5 1b/3 month interval
3. 1.5 1b/6 month interval
4. 4 lbs/6 month interval

C. Renovation of leatherleaf fern.
Replanting times of fern beds varies considerably. Growers have
reported replanting beds as early as 5 years, but others have cut from
beds for 20 years without replanting. Seven to 10 years appear to be
the most common. The beds used here were 5 years old at initiation of
the experiment. Yield has been taken continuously. The following
treatments were included.
Treatments
1. Control no renovation.
2. Replanted Sept. 1979.
3. Replanted Sept. 1980.
4. Replanted Sept. 1981.
5. Replanted Sept. 1982.
6. Clear cut Sept. 1979 and Sept. 1981.
7. Strip cut, alternate 6 in, 6 mo.
8. Strip cut, alternate 6 in, 12 mo.
Experiment initiated: Sept. 7, 1979.

Treatments 2, 4, 6 and 8 receive an additional inch of water
each week.

E. Renovation time of clear cut.
A second renovation experiment was initiated to determine time of
clear cutting on yield of fern. Clear cutting fern has several advan-
tages: 1) old, diseased and misshapen fronds are removed; 2) many weeds
are eliminated; 3) remaining weeds are more easily removed; and 4) young
emerging fronds are free to grow unobstructed. There are also disadvan-
tages: 1) all young expanding fronds are removed so that harvest of
marketable fronds is delayed; and 2) young emerging fronds appear to be
smaller. This test was initiated to determine differences between clear
cutting in February (Treatment 1) when fern are growing slowly, March
(Treatment 2) or April (Treatment 3) when fern are growing more rapidly.
Treatment 4 had only older unmarketable fronds removed in February.
Treatment initiation: February 10, 1982.

F. Frond age, season of cut and keeping quality of leatherleaf fern.
To establish the effect of frond age and time of cut on wilt of
fern, emerging fronds (fiddleheads) are marked and subsequently harves-
ted at 6, 10, 14, 18, 22 and 26 weeks from fiddlehead stage. This
process is initiated with new fiddleheads every 4 weeks and will con-
tinue for 1 year. Results are not yet available.
Initiation date: April 19, 1982.

Location 15
A. Effect of soil pH and minor elements on yield and vase life of leather-
leaf fern.
Research is in progress to determine effect of soil pH on avail-
ability of nutrients and their relationship to fern wilt and yield.
Fern is grown under 73% polypropylene shade and fertilized with 1000 Ib
N/A/yr from 19-6-12 (N-P205-K20) granular fertilizer. Soil pH is

maintained at 4.5, 5.5 or 6.5. The availability of aluminum, boron,
copper, iron, manganese, molybdenum, zinc and a combination of these
7 elements will be monitored. Data obtained to date indicate that
rate of establishment from planting rhizome pieces is depressed by
low pH (4.5) with considerable rhizome loss.
B. Fertilizer timing and rate.
Fertilization of leatherleaf fern was formerly accomplished by
slow release type fertilizer such as manure and dry organic fertilizers.
Today, many growers fertilize frequently with a rapidly available liquid
fertilizer. To determine effect of frequency and rate of fertilization
on yield and fern wilt, an experiment was initiated with Osmocote and
liquid fertilizer. Results are not yet available on this trial as it
was started in July, 1982.

BREEDING PROGRAMS
Discussion Leader R. J. Henny, Geneticist
Location 7
A. Aglaonema and Dieffenbachia hybrids.
Several advanced selections of Aglaonema and Dieffenbachia hybrids
will be on display. Each hybrid has been selected for propagation and
testing for future release to industry. Visitors comments concerning
merits of different plants are encouraged. Research reports concerning
breeding techniques can be ordered at location 8 for those interested in
making their own hybrids (82-16, 82-22). Breeding studies with other
plants will also be discussed.

B. Inducing lateral branching of Aphelandra and Peperomia.
The synthetic cytokinin N6-Benzylaminopurine (BA) was applied in
a single spray to newly propagated Aphelandra squarrosa 'Dania' and
Peperomia obtusifolia plants to see if BA would induce lateral branch-
ing. Treatment concentrations ranged from 0-500 ppm and each plant
was sprayed to runoff. Both cultivars had increased branching due to
BA treatment. Treated plants will be displayed plus experimental data
relating to number of breaks and cost of BA treatment. A handout
summarizing these experiments will also be provided.

C. Hormones stimulate rooting of Aglaonema 'Fransher' and Aphelandra
squarrosa 'Dania'.
Cuttings of Aglaonema 'Fransher' were tested for their rooting
response to 3 levels of Hormodin5 rooting powders versus an untreated
control. Experiments were conducted during the spring and fall of
1982 and winter 1983. Tests were conducted in a heated propagation
bench at 26-300C (79-860F). Data consisted of countingthe total
number of roots per cutting and the length of the longest roots after
5 weeks in the propagation bench. Results from 3 separate tests have
been combined in the following table.

Table 1. Effect of 3 different hormones on rooting of Aglaonema
'Fransher'.

a. woos** ago** agasgasgs-Rosanaag a. a a a's q. a aa*&** aa@we** & asa...* woes *.S a*** a a.a.aas.. as. as. &*&*.a gas. ,
PATHOLOGY PROGRAMS
Discussion Leader A. R. Chase, Plant Pathologist
Location 2
A. Pseudomonas leaf spot of Schefflera arboricola.
Until the winter of 1983, no known bacterial diseases had been
identified on any members of the Schefflera family. During that winter,
however, Dwarf Schefflera were collected with a severe leaf spot re-
sulting in larbe black lesions and leaf drop. The causal bacterium
has been identified as Pseudomonas cichorii, a pathogen which also
causes diseases on Chrysanthemum, Gerbera Daisy and many Philodendron
and their relatives. This display demonstrates the symptoms of this
disease on Schefflera arboricola and relatives as well as Chrysanthe-
mum and Gerbera Daisy.

B. Corynespora leaf spot of Ficus spp.
Corynespora cassiicola has been a moderately serious leaf spot
pathogen of Aphelandra for many years. Recently, Aeschynanthus
pulcher and several related plants were also identified as hosts of
this fungal pathogen. In the summer of 1982, samples of Ficus spp.
were found with a serious leaf spot which was later identified as
Corynespora leaf spot. This is the first serious leaf spot disease
of Ficus benjamin which has been identified. This display shows
typical symptoms of Corynespora leaf spot on several Ficus spp.,
as well as symptoms on Aphelandra and Lipstick vines.

In general, both Aphelandra and Lipstick vine are less severely
infected if plants are not artificially wounded. Ficus spp., however,
are infected easily in the absence of wounding.

Plant

C. Phytotoxicity of Acephate on Spathiphyllum based on fertilization of
the plant.
Although Spathiphyllum is labeled for use of Acephate insecticide
(Orthene), it is not always safely employed. These trials demonstrate
the importance of accurate fertilization in safety of pesticide appli-
cation. Generally, the higher rates of fertilization of Spathiphyllum
result in greater Acephate damage, typified by marginal burning and
necrosis in the whorl where new leaves have been exposed to the pesti-
cide. Plants were fertilized with 19-6-12 Osmocote.

Fertilizer rate
for 5" pots

Acephate level

Damage index

0 g 1.5 g/gal 1.9
3 g 2.0
6 g 2.6
9 g 2.9
12 g 3.4
15 g 4.1

= recommended rate

D. Temperature and severity of Myrothecium leaf spot of Dieffenbachia.
Myrothecium leaf spot of foliage plants can be very severe under
certain environmental conditions. The role of temperature was tested
on Dieffenbachia by growing and inoculating plants at the following
temperatures: 65, 70, 75, 80, 85 and 900F. The disease was most
severe when temperatures were between 70 and 80F. The disease is
therefore more prevalent during the spring and fall than during the
summer and winter, and disease control measures should be concentrated
during times when these temperatures prevail.

Temperature (oF)

Severity scale
Test 1 Test 2

65 5.2 6.0
70 7.8 4.8
75 6.6 7.4
80 4.6 3.4
85 3.8 1.4
90 0.4 1.8

E. Controlling bacterial blight with vinegar.
Many times growers develop control strategies on their own which
can be evaluated here at the research center. Although the methods
employed may not be identical, these tests serve to establish the
validity of such trial methods in a manner in which growers usually
cannot perform them. The test on display was designed to evaluate
the efficacy and safety of using dilute vinegar as a bactericide for
controlling Erwinia blight on Philodendron selloum. Compare the
treatment with the use of more commonly accepted bactericides and you
may decide which is best for controlling this bacterial leaf spot
disease.

Treatments Rate/gal. Disease severity rating

Water ---
Vinegar 10%
Agristrep 200 ppm
Kocide .01 Ib

Results were not available at the time of this printing.

Location 11
A. Plant pathology programs for disease control.
There are numerous leaf spot diseases of foliage and cut foliage
plants which are currently controlled through applications of fungi-
cides. In some cases, control is easily accomplished while in others,
control is difficult due to sensitivities of the host plant to avail-
able fungicides or a lack of fungicides for good control of that
disease. Past research has led to identification of many fungicides
which effectively control certain diseases. This has frequently
resulted in expansion of labels of many fungicides to include numerous
'foliage plants. Since new fungicides are being developed each year
and "new" diseases appear each year, the need for testing products
for efficacy and phytotoxicity is constant.
On display today we have several examples of such efficacy trials
using both chemicals which are currently lableed for use on foliage
plants and some which are not labeled.

1 = no disease, 4 = severe disease.
Conclusions: All three fungicides provide good control of Corynespora
leaf spot of Ficus.
Research reports 82-4, 82-10, 82-12, 81-18, 82-24 and 83-2 all
deal with efficacy and phytotoxicity of fungicides for control of
foliage plant diseases. These reports are on display at location 8
where they can be ordered.

HORTICULTURE PROGRAMS

Discussion Leader R. W. Henley, Foliage Extension Specialist
Location 3
A. Soil and air temperature effects on growth of Dieffenbachia.
Research on effects of soil heating on growth of foliage plants
is limited and no data have been reported on the interaction between
soil temperatures and different air temperatures. This experiment

utilizes 4 soil temperatures, 55, 65, 75, and 85*F; and 2 night time
minimum air temperatures, 55 and 650F. Dieffenbachia was selected
as the test plant because previous research had shown poor plant
growth at air temperatures of 600F or below when the soil temperature
was the same as the air temperature.
Data collected during the first year of this research project
(1981-82) indicated that best plants were produced at 750F soil and
650F air temperature. All plants produced at 550F air temperature,
except those at 850F soil temperature were inferior in quality. The
results from this year's experiments (1982-83) are similar and you
should be able to observe differences in plant color, size, and number
of suckers between the various treatments.
Based on 2 years data, it appears that 550F air temperature is
too low for growth of Dieffenbachia even at soil temperatures as high
as 850F. Our present suggestions would be air temperatures of 60 to
650F'and soil temperatures of 75 to 800F.

B. Influence of soil temperature on copper uptake.
Research conducted at this research center has shown that copper
deficiency is responsible for a serious production problem on Aglaonema
'Fransher'. Chlorosis, strapping, distortion, and dwarfing of terminal
leaves often occur during cool winter months, in spite of normal copper
applications. This research has been established to determine what
effect soil temperature has on uptake of copper. Soil temperatures of
55, 65, 75, and 85F and copper levels of 0, 25, and 50 Ibs/A equivalent
are being used. Data from trials conducted in the first year (1981-82)
showed that copper uptake was reduced at soil temperatures of 55 or 650F.
Overall growth was also severely reduced at these soil temperatures,
even when additional copper was applied to overcome deficiencies.
Although it is fairly late in the season and warm weather has
overcome some of the treatment effects, it is still possible to observe
copper-induced chlorosis of plants grown at cool soil temperatures.

C. Cold interrupted warm night regimes.
Producers interested in saving energy have attempted to reduce
heating costs by lowering night temperatures. In most instances, this
has not worked with foliage plants, as increased turnover time has
eliminated energy savings. This research was established to determine

whether one or three nights a week of low temperatures would affect
plant growth and turnover time. Dieffenbachia, Epipremnum and
Spathiphyllum were subjected to 45 or 500F one or three nights a week
and compared to check plants grown at 60 or 650F.
Previous research on Brassaia indicated that one cold night per
week was not damaging. Dieffenbachia in this experiment were severely
damaged by either one or three cold nights a week. Results on
Epipremnum and Spathiphyllum will be presented.

D. The poly-pot-pack.
A technique of plant production in a prepackaged unit of peat-
lite mix or similar growing medium (the poly-pot-pack) is displayed.
Advantages of the technique include improved sanitation, conservation
of water, fertilizer and plastic, and savings of weight and bulk in
shipping. Research data generated thus far suggests the new container-
pack is most likely to find application with high value crops which
are shipped long distances.

Location 6
A. Chilling damage on Dracaena marginata.
Plants were grown under 47, 63 or 80% shade in a shadehouse or
80% shade in a greenhouse on 1800, 3600 or 5400 Ibs N/A/yr. After
nine months growth, plants were subjected to simulated shipping of
7, 14, 21 or 28 days at 450F after which they were placed in this
greenhouse to observe treatment effects. Note that less chilling
damage occurred on plants grown under higher shade levels, and that
chilling damage increased with duration of exposure.

B. Foliar mottling of Philodendron scandens oxycardium.
This research was established to determine a cause for foliar
mottling which has appeared in several nurseries. The symptoms are
somewhat similar to red-edge, a bacterial disease, but no disease
organism has been isolated. Tissue analyses of affected leaves com-
pared with normal leaves indicated excessive levels of micronutrients,
especially copper. We have been partially successful in reproducing
symptoms with excess copper application, but we are not sufficiently
sure to make this a recommendation at present. Plants on display have
been treated with excessive levels of each of the micronutrients.
Please observe the results and see if you agree with our observation
pertaining to copper.

Locations 16 and 17
Discussion Leader C. A. Conover, Ornamental Horticulturist
A. Use of melaleuca as a component of potting media and effects of
irrigation level.
In recent research, we have examined effects of irrigation rate
as well as time of irrigation prior to shipping on postshipment quality.
This research on Ficus benjamin, compared effects of 13 potting media
and 2 or 4 irrigations per week on growth and postharvest shipping
quality. All plants were of very high quality at the end of the growth
phase. They were subsequently placed in a simulated shipping environ-
ment for 28 days at 550F and then moved to holding rooms with 150 ft-c
for 12 hours per day. Results will be discussed (data were not
complete at time of printing).

Notes:

B. Long-term shipping and storage of foliage plants.
Research initiated during 1980 and conducted through the present
time has indicated that many foliage plants can be stored or shipped
in the dark for periods up to 28 days without significant loss of
quality. Temperature is a key factor and suggested shipping temper-
atures (F) for acclimatized foliage plants are given on the following
table. See research report 83-1 and 83-3 for additional information
as well.